Recent evidence has suggested that there may be long-term adverse health effects associated with weight fluctuations but further research is needed. The aim of this pilot project is to develop and evaluate methodology for the measurement of change and variability in body weight among adult men and women in the Framingham Heart Study Cohort and the Framingham Offspring/Spouse Cohort. This includes evaluation of a brief weight history questionnaire administered in two examination cycles of the Offspring/Spouse Cohort, description of prevalent weight history patterns in both cohorts, and development of a new instrument for more comprehensive assessment of weight history, including details on intention, means, timing, and extent of weight change. Measures obtained will be used in analyses examining the relations determinants of weight change as well as prospectively with a variety of health outcomes. In addition, the newly developed instrument for assessing weight history will be administered to the Framingham cohorts at the next interview cycle, and may be administered in other large cohorts as well, providing data for future analyses. The propose project will make important contributions to the study of health effects of weight change patterns among adult Americans.